Copy sheet moistening means for duplicating machines



Feb. 25, .1947. A J, LEVENH'AGEN 2,416,449

COPY SHEET MoIsTENING MEANS FOR DUPLICATING MAHINES Filed Sept. 28, 1944 2 Shee-cs-SheeI 1 Feb. 25', 1947. YA. J. Lr-:vENHAGl-:N y 2,415,449

COPY SHEET MOISTENING MEANS) FOR`DUPLICATI-NG MACHINES Filed sept. 28, 1944 2 sheets-sheen 2 Patented Feb. 25, 1947 COPY SHEET Mols'rENrNG MEANS Foa DUPLICATING MACHINES Arthur J. Levenhagcn, Chicago, Ill., assignor to Ditto, Incorporated, Chicago, lli., a corporation of West Virginia Applicationv September 28. 1944, Serial No. 556.105

(Ci. 91-49l' 8 Claims. l

The present invention relates to moistening devices for use in so-called liquid type duplicating machines wherein the copy sheets are moistened with a solvent for the copying ink that is deposited on the master sheet carried by the duplicating drum.

The problem of adequately supplying moisture to the copy sheets as they are fed to the master sheet has beenthe subject of considerable research, It is a principal source of trouble in liquid type duplicating machines. The controlling factor in regulating the delivery of a rather Fixed quota of liquid to each sheet, while avoiding the build up of a large excess of liquid on the moistening roller, or an element in contact thereof, lies in denitely limiting the amount oi liquid which is delivered to the moistening roller. wick feed can be used but the wicks clog and have to be replaced. I prefer to avoid such construction by pumping the liquid from a reservoir and spreading it upon the moistening roller.

In starting the duplicating operation it has been necessary to rst moisten the roller and the liquid spreader. It is desirable to do this by using the same amount of liquid that is needed in running. In the past it has been necessary to do a certain amount of priming where a spreader of an absorbent type has been employed with a smooth moistening roller, because the spreader took up too much of the liquid. I have developed a combination of a roughened or pitted rollerwith a sponge neoprene or rubber spreader that avoids the necessity of excess charges of liquid in priming and makes it possible to begin making adequately bright copies much more quickly without charging the spreader with a lot of liquid that may cause trouble afterward.

In my prior Patent No. 2,266,880v the advantages of utilizing sponge rubber as a spreader in combination with the moistening roller are described. The particular rubber described in the specification is a synthetic rubber sold under the name of neoprene. I nd, however, that with the construction described in my prior patent, while it enabled me to make a limited number of excellent copies, it did not suiliciently control the liquid distribution. It is the purpose of this invention to provide a novel combination between the moistening roller and the spreader so as to establish uniform coating of the copy sheets with a light enough coating to avoid breaking down of the master sheet and a heavy enough coating to make good legible copies. The sponge rubber or neoprene has no capacity for absorbing liquid solvent. It, therefore, does not function like a 2 fibrous wick for moistening. One cannot transfer the liquid through it by capillary attraction to the moistening roller, furthermore only a small amount of liquid will be contained on the surface of the sponge rubber I find that in using a sponge rubber spreader with a smooth hard moistening roller, there is a build up of the liquid between the roller and the lower end of the spreader immediately after priming so that there Y is a tendency to over moisten the roller and provide a limited number of very brilliant copies. Moreover, when a high speed drum is used with a moistening roller that is smooth and a sponge rubber spreader is pressed against it, it was found that the iirst part of each copy sheet was quite bright but that there was actually a fading in the brightness toward the end of the sheet.

I nd that I can obtain an excellent result by utilizing a pitted hard Vmositening roller in combination with the sponge rubber spreader described in my Patent No 2,266,880. The pitted roller has tiny shallow pits throughout its moistening surface. It appears that the shallow pits in the roller take olf a specc quota of liquid at each revolution, and this liquid is smoothed out by the sponge rubber spreader which can be kept on the slightly dry side so that it will recover any excess of liquid. I set the spray control for the liquid to deliver a minimum amount of liquid such as would be necessary to run a large number of good copies. I find that it is necessary to do practically no priming because even upon the irst revolution of the roller the pits therein carry a certain amount of moisture over` to the copy sheet, and the sponge rubber spreader does not, even if dry, remove all of the liquid from the pits. The sponge rubber spreader naturally can hold a certain amount of excess liquid in the pockets on the surface thereof, and this fact helps to prevent too heavy moistening at the beginning of the sheet and to allow moistening at the finish.

The nature of my invention will appear more fully from the following description and the accompanying drawings wherein a preferred form of the invention is shown. It should be understood, however, that the drawings and description are illustrative only and are not to be taken as limiting the invention except insofar as it is limited by the claims.

In the drawings:

Figure 1 is a side view partly in section of the duplicating apparatus embodying my invention;

Figure 2 is an enlarged fragmentary sectional view of a portion of the duplicating machine illustrating the copy sheet moistening mechanism;

I shown as applied to a liquid type' duplicating machine wherein the numeral -Ill Aidenties the duplicating drum on which a master sheet I| is secured. The drum has suitable gripping means I2 for attaching the master sheet. A platen roller I3 is positioned to engage and press copy sheets against the master sheet on saiddrum. The machine also embodies two combined feeding and moistening rollers I4 and I5 which are adapted to advance copy sheets from a feed tray I6 to the point where the platen 4roller I3 and the drum meet. The roller I is the moistening roller and is adapted to supply a solvent liquid tothe surface of the copy-sheet as it is advanced. It is non-absorbent and may be of neoprene with a shore hardness of about 45. A receiving tray Il receives the copy sheets after they have been brought in contact with the master on the drum. The combined moistening and feeding rollers I4 and I5 are driven by suitable gearing connected with the drum and identified by the numerals I8, I9 and 20.

The supply of moisture to the moistening roller I5 is accomplished by means of a pump 2| which pumps liquid from a reservoir 22 through a conduit 23 to a. spray pipe 24. The spray pipe 24 is mounted directly over the moistening roller I5 and has spray openings 25 for directing liquid down against the moistening roller. The pump 2| is driven from a cam 26 that rotates with the drum I0. The cam actuates a lever arm 21 which in turn raises a pump lever 28, there being a spring inside the pump chamber 2| to force the pump piston down after it is raised by the lever. The piston stem is shown at 29. It is not believed to be necessary to show the details of the pump mechanism since they are similar to those shown in my prior patent herein referred to. l i

It will be noted that the roller I5 is completely covered'throughout its surface with tiny depressions or pits 30. These pits may takel any suitable form; they may be round, they may be long grooves, or they may be irregular. Any roughening which gives small depressions may be used. It is advisable,- however, that the pits be suiiiciently tiny to be smaller than any particular area that would be occupied by a character on the copy sheet. They are much smaller than indicated in Figures 3 and 4 of the drawings. These fine pits or indentations are necessary in conjunction with a spreader in order to assure you of an adequate and uniform supply of liquid. This, is particularly true when the spreader is a sponge rubber. The sponge rubber does notvhave capacity to absorb the liquid but it is quite yielding and it spreads itself over quite a large surface on the moistening roller at al1 times. This presents a substantial number of pockets in the sponge rubber to the roller surface so that the liquid that piles up in the trough between the roller and the sponge rubber can be stored in the pockets and in the pits of the moistening roller.

The sponge rubber spreader is shown at 3| in the drawings as comprising a sheet of sponge neoprene or sponge rubber. Preferably I utilize a sponge rubber having fine pockets or holes therein since it is obvious that large openings in the sponge would not make for uniform distribution. Sponge rubber is peculiar in that when pressed down it tends to close the pockets at its surface so that a good wiping or spreading action is attained. The sheet 3| is carried by a `backing strip 32 and a clamping strip 33 all of which are carried by .two pivoted arms 34, only one of which is shown. Pressure is applied to the sheet 3| by means of a spring 35 which may be adjustable.

In the form of the invention shown in Figures 1 and 5 the sheet 3| is replaced by a roller 36 which is also of sponge rubber. This roller is mounted to turn in suitable journal boxes 31 at its opposite ends. It may be adjusted towardand away from its moistening roller I 5 by screws 38.

\ Means are now available for controlling the amount of liquid supplied by the spray pipe 24. Such means are illustrated in the patent to Kokay No. 2,337,721. This control is quite accurate but the suction type mechanism used increases the expense. I iind that it is possible with the present device to gauge the liquid supply closely enough to enable the sponge to carry a suflicient Dart of it to complete the moistening of a sheet after the pump stroke is over. In oth'er words, I can cut the'liquid supply down sufliciently to make it unnecessary to withdraw any of it, and the pitted surface of the sponge and the moistening roller will cooperate to distribute the limited liquid supply uniformly to the copy sheet. I find that using the roller 36 has the advantage that it provides a greater amount of surface of the sponge in which to store a limited amount of liquid so that the adjustment of the supply of solvent is not quite so critical as it is with the sheet type of sponge rubber. I find it unnecessary to provide drainage facilities to drain oi any excess liquid and, in fact, the excess liquid which had to be drained off would defeat the purpose of my invention to a substantial degree for the reason that it would .tend to overload the sponge rubber more quickly. Y

The specific brief explanation to which I attribute the success of this moistening device compared with my own prior patent and other moisteners is that the pits in the moistening roller provide one reservoir which is continually available to supply the proper amount of moisture to the copy sheets. This amount is controllable by the pressure between the moistening roller and the spreader. The sponge rubber spreader provides another reservoir which is available to the reservoirs formed by the pits in the moistening roller when the spray has been cut off. Thus with this apparatus I have a continuous filling and refilling of two sets of pockets; one set being on the moistening roller and the other set being on the spreader. With such an action there is suiicient storage in the` spreader to feed the reservoirs in the moistening roller before the period after thev spray is cut off. Likewise, there is sucient capacity 0b-` tainable in the sponge rubber to store an adequate amount of moisture.

My invention avoids the necessity for using return drains, end seals, etc. The sponge rubber roller is more satisfactory than a wick be, cause the continued compression and expansion of the sponge rubber keeps it live and functioning well. Also the constant scrubbing action between the pitted surface ofthe moistening roller and the sponge rubber prevents any caking of lint or dirt. The limited amount of solvent left in the sponge rubber when the machine is stopped presents no leakage problem. The' solvent supply is in the pump supply tank and does not evaporate.

In the foregoing specification and in the claims I use the term sponge rubber to include both natural rubber and synthetic rubber compositions and mixtures embodying -both natural and synthetic rubber.

It is believed that the foregoing description wil1 make the nature and advantages of my invention clear to those skilled in this art.

Having thus described my invention I claim:

1. Moistening means for applying a film of liquid to one face of a sheet comprising a moistening roller adapted to engage and roll over the said face, a spreader in pressure engagement with the downwardly moving face of the moistlening roller, and means to deliver a quantity of liquid into the trough formed by said roller and member, said roller having a pitted surface and said spreader member comprising sponge rubber.

2. Moistening meansffor applying a film of liquid to one face of a sheet comprising a moistening roller adapted to engage and roll over the said face, a spreader in pressure engagement with the downwardly moving face of the moistening roller, and means to deliver a quantity of liquid into the trough formed by said roller and member, said roller having a pitted surface and said spreader member comprising sponge rubber, the moistening roller being non-absorbent and relatively hard whereby the pressure of the spreader thereon compresses the spreader and causes it to cover a number of the depressions in the moistening roller surface at all times.

3. Moistening means for applying a film of liquid to one face of a sheet comprising a moistening roller adapted to engage and roll over the said face, a spreader in pressure engagement with the downwardly moving face of the moistening roller, and means to deliver a quantity of liquid into the trough formed bysaid roller and member, said roller having a pitted surface and said spreader member comprising a sponge rubber roller.

4. Moistening means for applying a lm of liquid to one face of a sheet comprising a moistening roller adapted to engage and roll over the said face, a spreader in pressure engagement with the downwardly moving face of the moistening roller, and-means to deliver a quantity of liquid into the trough vformed by said roller and member, said roller having a pitted surface and said spreader member comprising a sponge rubber roller, the moistening roller being non-absorbent and relatively hard whereby the pressure of the spreader thereon compresses the spreader and causes it to cover a number of the depressions" in the moistening roller surface at all times.

5. Moistening means for moistening copy sheets as they advance to a duplicating drum, said means comprising a moistening roller, a counter roller for holding a copy sheet against the moistening roller, a spreader member of sponge rubber engaging the surface of the moistening roller y to press into the sponge rubber and extract liquid from the pockets in the surface thereof when the depressions in the roller are unfilled.

6. Moistening means for moistening copy sheets as they advance to a duplicatingdrum, said means comprising a moistening roller, a counter roller for holding a copy sheet against the moistening roller, a spreader member of sponge rubber engaging the surface of the moistening roller in advance of its engagement withv the copy sheet, means pressing the spreader member against the moistening roller whereby to compress that portion of the member engaging the roller, and means to deliver a measured quantity of liquid intermittently to the trough between the spreader member and the rollersaid moistening roller having a pitted surface providing non-deformable pockets to receive the liquid and the moistening roller being non-absorbent and relatively hard whereby to press into the sponge rubber and extract liquid from the pockets in the surface thereof when the depressions in the roller are unfilled, the depressions in the moistening roller surface being varied in form and position.

7. Moistening means for applying a film of liquid to one face of a sheet comprising a moistening roller adapted to engage and roll overthe said face, a spreader in pressure engagement with the downwardly moving face of the moistening roller, and means to deliver a quantity of liquid into the 'trough formed by said roller and member, said roller having its surface roughened to provide a multitude of tiny depressions of fixed size and said spreader member comprising a sponge rubber roller, the moistening roller being non-absorbent and relatively hard whereby the pressure of the spreader thereon compresses the spreader and causes it to cover a number of the depressions in the moistening roller surface at all times.

8. Moistening means for applying a lm of liquid to one face of a sheet comprising a moistening roller adapted to engage and roll over the said face, a spreader in pressure engagement with the downwardly moving face of the moistening roller, and means to deliver a quantity of liquid into the trough formed by said roller and member, said roller being non-absorbent and having its surface roughened and said spreader member comprising sponge rubber.

ARTHUR J. LEVENHAGEN.

REFERENCES CITED The following references are of record in they le of this patent:

Kokay Dec. 30, 1941 

